电子废弃物聚丙烯制备木塑复合材的研究

探讨了电子废弃物聚丙烯(PP)制备木塑复合材料(WPC)的可行性及其主要影响因子。研究结果表明:电子废弃物PP具备制备木塑复合材料的可行性,PP和木纤维混合比例是影响WPC性能的关键因子之一,加入适量的PPg-MAH有利于提高WPC的力学性能,并大幅度降低其吸水性,当PP与木纤维比例为60∶40,PP-g-MAH使用量为10%时,WPC可获得较好的综合性能指标。     

Persistence of metaflumizone on cabbage (Brassica oleracea Linne) and soil, and its risk assessment

Metaflumizone is a novel sodium channel blocker insecticide of semicarbazone class. It provides good to excellent control of most of the economically important lepidopterous pests and certain pests in the orders Coleoptera, Hemiptera, Hymenoptera, Diptera, Isoptera, and Siphonaptera. Although metaflumizone has been marketed globally for several years and got registered in India in the year 2009, specifically for the control of DBM on cabbage, to our knowledge, no food safety aspects of metaflumizone residue on cabbage have ever been reported in the literature in India or elsewhere. The present study was undertaken to evaluate the persistence of metaflumizone on cabbage and soil, vis-a-vis its risk assessment, following two spray applications of metaflumizone 220 SC (Verismo®), each at recommended and double dose of 200 and 400 g?a.i.?ha^?1 respectively. Initial residue deposits of metaflumizone on cabbage were 0.46 and 0.51 mg?kg^?1 at recommended and 0.76 and 0.85 mg?kg^?1 at double the recommended dose following the first spray and second spray application. The residues persisted beyond 5 days from both the treatments and dissipated with the half-life ranging from 1.7–2.1 days. Initial deposits of metaflumizone on soil ranged from 0.23–0.37 mg?kg^?1 and degraded with a half life ranging from 4.0–4.8 days. No degradation product of metaflumizone was detected in cabbage and soil at any point of time. Soil samples collected from the treated field after 7 days were free from any residue of metaflumizone or its metabolites. A pre-harvest waiting period of 3 days after application was suggested based on calculation of theoretical maximum daily intake.     

Bagasse-assisted bioremediation of ammonia from shrimp farm wastewater.

Development of new economically feasible ecofriendly products from agricultural wastes or byproducts for shrimp farm wastewater treatment is the objective of our continued research. Ammonia is a nitrogenous toxicant, which is commonly found in wastewater from shrimp farms. In the present study, we explored the possibility of the use of simply and inexpensively prepared bagasse products so that this abundant crop byproduct could be used to remove ammonia from shrimp farm wastewater. Bagasse, a natural highly fibrous lignocellulosic byproduct of sugarcane, was converted into five different products. Experimental results have shown that ammonia is efficiently removed from wastewater by four bagasse products with a dose of 1 to 6 g/L within 24 hours. The effect of bagasse products on other water quality parameters and growth kinetics of biofilm bacteria onto bagasse fiber have also been studied. Efficacies of products were compared by using statistical analysis. Products developed from bagasse are useful and economical.     

基于BDPs的多级土壤渗滤系统处理受污染河水的试验研究

针对受污染的流入滇池的河流河水,采用具有曝气段和缺氧段的两段式多级土壤渗滤(multi-soil-layering,MSL)系统,开展了在缺氧段添加非水溶性可生物降解多聚物(BDPs)材料PBS颗粒的强化脱氮除磷研究.结果表明,添加PBS碳源可有效解决传统MSL系统因碳源不足而导致的脱氮效果不理想的问题.在河水污染较轻及较重两种情况下,系统对TN的平均去除率分别达到78%、85%,平均单位表面去除负荷分别为9.09g·m-·2d-1、24.55g·m-·2d-1;TP平均去除率分别达到92%、98%,平均单位表面去除负荷分别为0.76g·m-·2d-1、2.02g·m-·2d-1.此外,系统对COD的平均去除率可达到75%以上.     

西安市大气降水的主要化学组分及其来源

为认识西安市大气降水主要化学组分的现状,对2019年西安市市区和郊区大气降水样品的pH值、电导率、水溶性离子和重金属的质量浓度、湿沉降通量和来源进行了研究.结果表明,西安市冬季大气降水pH、电导率、水溶性离子和重金属浓度均高于其它季节.降水中主要的水溶性离子为Ca²⁺、 NH⁺₄、 SO■和NO^-₃,其之和占总离子浓度的(88.5±2.8)%;市区和郊区主要重金属是Zn和Fe、 Zn和Mn,其之和分别占总金属浓度的(54.0%±3)%和(47.0%±8)%.市区和郊区降水中水溶性离子的湿沉降通量分别为(253.2±58.4)mg·(m²·month)^-1和(241.9±61.1)mg·(m²·month)^-1,呈现出冬季高于其他季节的特点;重金属的湿沉降通量分别为(86.2±37.5)mg·(m²·month)^-1和(88.1±37.4)mg·(m...     

Carcinogenicity of hexachlorocyclohexane (BHC) in pure inbred swiss mice.

Inbred Swiss mice were treated with technical BHC (1) orally with the diet or by intubation and (2) by skin painting. The total duration of the experiment was 80 weeks. There was no difference in body growth and mortality between the experimental and control groups. Symptoms of intoxication in the form of convulsions and tendency of circling in one direction with drooping ears were observed alongwith corneal opacity 40 weeks after the experiment. Oral BHC treatment resulted in a significant increase in the incidence of liver tumours and tumours of lymphoreticular tissue. Males and females were equally susceptible. Skin painting of mice did not significantly increase the incidence of tumour.     

A comparative study on the dissipation and microbial metabolism of organophosphate and carbamate insecticides in orchaqualf and fluvaquent soils of West Bengal

An experiment has been conducted under laboratory conditions to investigate the effect of phorate (an organophosphate insecticide) and carbofuran (a carbamate insecticide) at their recommended field rates (1.5 and 1.0 kga.i.ha-1, respectively) on the growth and multiplication of microorganisms as well as rate of dissipation and persistence of the insecticidal residues including their metabolites in laterite (typic orchaqualf) and alluvial (typic fluvaquent) soils of West Bengal. Application of phorate and carbofuran in general, induced growth and development of bacteria, actinomycetes, fungi, N2-fixing bacteria and phosphate solubilizing microorganisms in both the soils and the stimulation was more pronounced with phorate as compared to carbofuran. Application of phorate recorded highest stimulation of fungi in laterite and actinomycetes in alluvial soil. Carbofuran on the other hand, augmented fungi and N2-fixing bacteria in laterite and actinomycetes in alluvial soil. Bacterial population was inhibited due to the application of carbofuran in alluvial soil. Phorate sulfoxide and phorate sulfone, the two metabolites of phorate and 3-hydroxycarbofuran and 3-ketocarbofuran, the two metabolites of carbofuran isolated were less persistent in both the soils. Phorate persisted in laterite and alluvial soils up to 45 and 60 days, respectively depicting the half-life (T1/2) 9.7 and 11.5 days, respectively while the T1/2 of carbofuran for the said soils were 16.9 and 8.8 days, respectively. No metabolite of carbofuran was detected in soils after 30 days of incubation while phorate sulfone persisted in alluvial soil even after 60 days of application of the insecticide.     

Chemical fractionation and heavy metal accumulation in the plant of Sesamum indicum (L.) var. T55 grown on soil amended with tannery sludge: Selection of single extractants

A pot experiment was carried out to study the single and sequential extractions of metals in different tannery sludge amendment and the potential of the plant of Sesamum indicum L. var. T55 (sesame) for the removal of metals from tannery waste contaminated site. The metal extraction efficiency obtained with each extractants was slightly different and follow the order; EDTA>DTPA>NH(4)NO(3)>NaNO(3)>CaCl(2). The correlation analysis between extractable metals in the different amendments of sludge and metal accumulation in the plant (lower and upper parts) showed better correlation for most of the tested metals with EDTA extraction. In this study, a sequential extraction technique was applied on different amendments of tannery sludge. The results showed that Mn, Zn, Cr and Cd were mostly associated with Fe-Mn oxide fraction in most of the amendments, K and Ni was found in residual (RES) fraction, Fe and Cu was bound with organic matter (OM) and RES fractions and Na was associated with carbonate (CAR) fraction. The metal accumulation after 60 d of growth of the plant was found in the order of K>Na>Fe>Zn>Cr>Mn>Cu>Pb>Ni>Cd and its translocation was found less in upper part. The accumulation of toxic metals (Cr, Ni and Cd) in the plants was found to increase with increase in sludge ratio, in contrast, the accumulation of Pb decreased. In view of growth parameters and metal accumulation in the plant, it was observed that lower amendments (25%) of tannery sludge were found suitable for the phytoremediation of most of the studied metals.